In the past 10 years, the share of homes worth a million dollars has increased in the United States.

Real estate site Zillow reports that there are more million-dollar ZIP codes (ZIP codes where at least 10 percent of homes are valued at one million dollars) now than at the housing-market peak in 2007.

"Of the 346 ZIP codes that crossed the million-dollar threshold after 2014, 114 (32.9 percent) are in six West Coast metros: Seattle, Portland, Ore., San Francisco, San Jose, Los Angeles, and San Diego. On the East Coast, four metros (New York, Boston, Miami, and Washington, D.C.) accounted for another 92 new million-dollar ZIPs (26.6 percent of the total)," Zillow report.

Tech hubs like San Francisco and San Jose have the most of these high-end ZIP codes. Connecticut's current collection isn't too shabby, but the state has actually seen an opposite trend than the country as a whole; there are less million-dollar ZIP codes in 2017 than there were in 2007.

According the the report, there are 25 million-dollar zip codes in the state now; in 2007, there were 30.

Not surprisingly, most are fund in Fairfield County, and Greenwich has the most with five ZIP codes.

Greenwich's richest ZIP neighborhoods include Old Greenwich, Riverside and Cos Cob. Litchfield County towns like Washington, Kent and Sharon also have their share of ritzy hoods.